A Guide to Aegis of the Hearth

[size=150]Aegis of the Hearth[/size]

After plenty of stuff in other threads I thought I would compile a list of what is explicitly true, implicitly true, implicitly likely (though not necessarily true), and generally accepted about Aegis of the Hearth, sort of like a FAQ. I'll try to color-code everything. I'll also include some common thoughts. I'll keep notes small and in black. I will update this first post as corrections are pointed out or additional things are found.


  • All spells cast toward the Aegis from outside it, bringing objects into the Aegis, or whose continuing presence is brought into the Aegis must penetrate the against the level of the Aegis unless cast by someone who participated in the Aegis ritual. [size=85]Invitations and tokens apparently do not help with this.[/size]
  • All spells cast within the Aegis suffer a penalty to their casting total of half the level of the Aegis unless cast by someone who participated in the Aegis ritual or someone with an invitation and token.


  • All powers used by magical creatures within the Aegis suffer a penalty to their penetration of half the level of the Aegis unless used by someone who participated in the Aegis ritual.

Implicitly true:

  • Invitations and tokens can reduce this penalty. [size=85]This is because the penetration penalty is define to be the same as the casting total penalty and the casting total penalty is reduced by invitations and tokens.[/size]

Implicitly likely:

  • Powers of beings from other realms suffer the same penetration penalties. [size=85]Nothing else about Aegis seems to distinguish between realms, and "magical" isn't capitalized, so it's probably supposed to be "supernatural" or something like that.[/size]
  • All powers sent toward the Aegis from outside it, bringing objects into the Aegis, or whose continuing presence is brought into the Aegis must penetrate the against the level of the Aegis unless sent by someone who participated in the Aegis ritual. [size=85]Powers and spells seem to be treated with the same penalties by the Aegis, so this was probably intended. Invitations and tokens apparently do not help with this.[/size]

Supernatural Abilities

  • For a Bjornaer to use Heartbeast within an Aegis opposing it, the Bjornaer must overcome 3+(Aegis magnitude). [size=85]It is interesting that this is not +(magnitude)/2 to be in line with the penalty to spells and powers[/size].

Implicitly likely:

  • Since it is stated in HoH:MC that Heartbeast is affected during the transformation because it is a supernatural effect at that moment, it is likely that other Supernatural Abilities used within a resisting Aegis will be similarly penalized. Additionally, HMRE specifies that hedge magician powers "cast" at or within an Aegis must overcome the Aegis similarly how spells noted above must. Many hedge magician effects come from Supernatural Abilities and are not spells, so this general statement likely applies to those Supernatural Abilities as well. [size=85]Note that Parma Magica is not countered by Aegis of the Hearth. This does not imply any Supernatural Abilities are not affected because Parma Magica is not a Supernatural Ability, plus it seems likely Aegis of the Hearth and Parma Magica were designed to be compatible.[/size]

Other Supernatural Virtues/Flaws
Implicitly likely:

  • If there's no Ability nor Art, the applied penalties seem irrelevant, so the Virtue or Flaw behaves normally.


  • If any of these three apply, the item is not resisted:
    [list][*]The item was made by someone who participated in the Aegis ritual.
  • The item was made by someone who has an invitation and token.
  • The item was inside the Aegis as the ritual was cast, regardless of who made the item.
    ]All other items are resisted in an unstated manner.[/*:m][/list:u]
    Implicitly Likely:
  • If you put the most weight on the word "resisted," then resisted items must penetrate the Aegis's level regardless of location. [size=85]This probably means Talismans cease to give their bonuses when within a resisting Aegis, too.[/size]
  • If you put the most weight on "foreign" vs. "within," then resisted items must penetrate the Aegis if "foreign" or have reduced penetration if within the Aegis. [size=85]This can be interpreted so that Talisman bonuses flicker as the boundary is crossed, being resisted in an essentially irrelevant way.[/size]

Might Beings

  • Creatures with Might less than or equal to the Aegis's level cannot move into the Aegis from outside it without an invitation/token or without having been part of the ritual. [size=85][strike]It is not stated whether or not the Aegis itself needs to penetrate like wards do for this effect. By default it would seem like the Aegis should have to penetrate for this effect, however, far more players play without the Aegis needing to penetrate than play with it needing to penetrate.[/strike] Through the Aegis has clarified this, stating Aegis of the Hearth must penetrate.[/size]
  • Revoking an invitation does not expel a person. It prevents the person from re-entering.

Implicitly true:

  • Persons, things, etc. with Might less than or equal to the Aegis's level cannot move into the Aegis from outside it without an invitation/token or without having been part of the ritual, as above. [size=85]If there is a prevention from re-entering, then it seems "person" and "creature" are interchangeable despite the apparent distinction being made between them.[/size]
  • Revoking an invitation does not expel a creature, thing, etc. It prevents the creature, thing, etc. from re-entering. [size=85]See the note above.[/size]

Implicitly Likely:

  • Powers in the familiar bond are essentially in an invested item and should be resisted in an unstated way (see above) unless one of the item exceptions (see above) is true. [size=85]Even then, due to the nebulous location of the power, there are questions. Who has to be inside the Aegis as the ritual is cast, one of the magus or familiar or both of them? If the one activating the effect is inside the Aegis and the other is outside the Aegis, is it resisted? Finally, what of the cords themselves? The nice thing about the using the "foreign" vs. "within" interpretation for items is that you can be consistent and have the cords remain: the cords will be resisted, too, but that just makes them blink as you cross the boundary, essentially meaning they keep working.[/size]

Longevity Rituals
Generally accepted:

  • The longevity ritual is not affected. [size=85]However, the question has come up more than once. The longevity ritual doesn't fit with items very well, though it seems somewhat that way when first done. However, renewed longevity rituals seem more like spells, though without a casting total. As with cords, if you go with the "foreign" vs. "within" interpretation for items you could allow longevity rituals to be similarly resisted in a pointless way, the value of which is that you don't need to worry about more classes of things vis-a-vis an Aegis.[/size]

For talisman: casting bonuses and form resistance, as for touch extension, are not arts or abilities. Thus, they are not hindered by aegis.

But, for example, casting bonuses are "effects from enchanted devices [which] are resisted." So they are most likely resisted by RAW. But I don't think anyone plays that way. Do you know of any statements in any of the books that go against "effects from enchanted devices are resisted" for non-invested talisman effects? It wouldn't surprise me if there is something somewhere, but I haven't found it.


Everything seems sensible to me and (Lazy noble's parma) right, AFAIK.

I'd just add a slight precision

While it is totally true that most players play without the Aegis needing to penetrate, as no exception is stated to the more general rule, it seems likely that it does. Which may bring its own problems. This is very reminiscent of the old days of "wards don't need to penetrate".

I still stand that the Aegis is a ward and accordingly needs to penetrate to effect as all spells need to penetrate to effect


There are several concepts in AM that are assumed to "work" to achieve The Order as described.

One is Parma Magica, another is Aegis.

So, despite any RAW or creative interpretation or deconstruction or "what your definition of "is" is" or "common sense" to the contrary, I start all my understanding from the belief that the Aegis works, and that that has to mean that there is no easy way around it.

That alone speaks against most ploys and flaws.

This assumes powers are spells, which I think is true.

You forgot HoH:S p104 which describes Supernatural Abilities more fully, as found by Vulcano in the previous thread. Since they have a Casting Total, they might suffer the full (non-magnitude) penalty.

They can't have a "casting total" because casting total require art + art where the major difference about arts and abilities mechanism is: art +art +bonus + charact and ability + bonus + charact.

The only exception is the "method and power" which are stated as abilities (including the specialisation) for an art mechanism.


  • arts have no specialties

  • normal arts experience as pyramidal

  • puissant art give +3

  • cautious may only diminsh botch dice to 1

  • deficient arts experience as pyramidal*5

  • sympathy traits may NOT be used.

  • abilities have specialties

  • normal abilities experience as pyramidal*5

  • puissant ability give +2

  • cautious may diminsh botch dice under 0

  • accelerated abilities experience as pyramidal.

  • sympathy traits may be used.

  • you may have "learn by mistake" for ability

This is what happens when you implicitly Noble's Parma your words. Read the page and weep, they do.

No, they write: "this is the equivalent to the casting total of a hermetic spell".
That is not "this is the casting total of a hermetic spell".

Hence, any other thing you read after is by comparison with the casting total, but is not the casting total.

The fact that they tend to use a streamlined terminology (a way of doing the authors changed when came HMRE) is to ease the reading of the rules.

Having a "casting total" when you are not casting anything but just matching an ease factor is just silly :wink:.

Its sufficiently proven after :
they speak of "summon animal roll", not "casting roll of summon animal".

And before:

  • core rule book says "ability are normally used by adding charact + ability + die roll and comparing to an ease factor" (ArM5 p62) and spell casting (ArM5 p81): "When casting a spell, success is determined from the maga's casting total". That is totally different formulae.

For abilities, you roll and compare to eases factor decided by the SG. The more the better for the success itself. EG: with awareness 15 you will certainly receive more information than for awareness 6.
For arts, you roll and match a level you know. The more the better for the consequence of the success (ie Penetration). The fact that your casting total is 100 for your fireball level 10 or 50 don't change the potency of the fire. It will, however, influence the penetration.

As I see it, the Aegis has roughly 3 different effects:

  • A ward-like effect, against creatures of might trying to enter it. IMS, it is resisted, just like any other ward.
  • A parma-like effect that stops incoming spells. It must be penetrated.
  • An aura-like effect that impedes foreign powers. Like any aura, it isn't resisted (this is mostly for convenience's sake: As far as I can tell, it probably should, but that imply magi would master Aegis for resistance)

So you read it. Aegis does not use the "hermetic" qualifier, the restrictions apply for all spells. Using Summon Animal, Whistle Up the Wind, or any other Supernatural Ability certainly creates a spell by the mundane definition and RAW offers no other.

No matter your opinion on what is true, you should agree this is at least of the implicitly likely class.

Yes. You'll notice it's not listed as explicit. However, Aegis of the Hearth refers to creature powers being "cast" several times, which is a word use for spells (spell casting). So Aegis of the Hearth is considering the powers to be spells. I would have downgraded this to explicitly likely if there weren't those comments, because powers aren't spells, but with respect to Aegis of the Hearth they seem to be.

I agree with the lack of the "Hermetic" qualifier. At the same time, Heartbeast is explicitly a Supernatural Ability and is not treated as having a Casting Total penalty (meaning half the level of the Aegis), but rather a different size penalty. So RAW does offer something "other," but not in a very definitive way. This is why I simply wrote "similarly" above, meaning not necessarily the same but being resisted in some fashion. I couldn't find anything conclusive one way or the other, and I couldn't even find a clear implication of what the penalty should be. If I allow myself to ignore the other possibilities in the process, I can make arguments for penalties of (Aegis level)/2, (Aegis magnitude), or (Aegis magnitude)/2.


Um... no.

Your conclusion may or may not be accurate, but this "logic" does not get us there. Your assumptions are based on more assumptions, and you are (possibly) completely mis-representing that section to begin with.

It never says that "creature powers are cast", not in so many words, not even once, not even close. What it says is...

  1. that creatures of magical might cannot enter an Aegis higher than their Might,
  2. that they can be invited in,
  3. that such "a person" is not affected by the casting penalty,*
  4. that withdrawing the invite subjects "the person" to the Casting Penalty.*
  • First, note that "such a person" is referring to either Creatures of MM or persons who have been invited in - or (possibly) both. But it's not at all clear which. If only "persons who have been invited", then your line of argument disappears just that fast - and no one (except the authors) can say which is so.

(I think two sections became combined into one here - one about Creatures of MM, and another on how invitations work (with a split somewhere between #1 and #'s 3 & 4, above). And that seam between the two is not perfectly clear where one commentary stops and the next starts. See also my comments below re "saving text".)

Further, if it's "obvious' that the term "persons" refers to any and all magical creatures (dragons, werewolves, demons, green slimes, whatever, all = "person"), the it's equally "obvious" that the use of the term "casting total" may or may not imply that they are "casting a spell" vs. "using a power", as appropriate to their type. It doesn't bother to say "person or creature", it may also not bother saying "casting a spell or using a power".

It's equally possible (and perhaps more likely?) that the authors are simply conserving text, and not turning this into a legalistic behemoth. In order to be perfectly, excruciatingly accurate, that half-page section would have easily doubled in size. Let's take this for example...

"...When approaching the border of an
Aegis, a magical person (including a Hermetic magus), feels a slight tingle..."
Now, read literally, that's saying that magi are "magical persons", and that would lead us to believe they are a Creature of the Realm of Magic - but we know that's not accurate, and we trust that's not what they meant. The authors/editors took a shortcut with language, knowing (well, assuming) that we would know what they meant since magi don't have MM, etc.

In the Bestiary section, you'll find strong evidence that Powers are not spells, but at the same time a much more convincing comment that supports your general conclusion.

Creature Powers
(p 191)
Creature powers are not Hermetic spells...
The penetration of a creature's powers depends on the creature's Might Score... (edit formula) ...

So, spell or no is irrelevant, the power must penetrate - I believe that's clear one way or the other.

This is the type of thing I'm talking about. I would have added "apparently", or put your commentary in pink as well. The RAW doesn't specify this, so it's all surmise, and not everyone would agree with it (even if also true that not everyone would have made such a close reading of the text - Respect for that, in any case.)

I think this is a good exercise - I agree with much of what you've written, and what little I might not agree with has allowed me a new, clearer perspective on considering it. I just don't think you, or "we", have a monopoly on any single "accurate interpretation", and I'd be more comfortable seeing language to that effect be included in the OP. But that's just me.

Tugdual, to be clear:

  • I agree that a penalty has to occur
  • i disagree only because I think that this penalty is magnitude/2 by comparison with level/2 for spells.

That's all the point of my "it's not a casting total".

Yeah, every saga should play it that way. It's just that RAW Aegis is broken and doesn't cover half the cases.


I'll agree to a downgrade. I've also noticed even more issues on my reread. It's drawing a distinction between creatures and persons, and not everything seems to apply to both. Such a distinction causes even more problems. Also, if the "such a person" and "the person" applies to magi, then magi who have been issued and invitation and had it revoked cannot re-enter the Aegis due to how it's written. Yes, the whole thing is a mess. I also seem to have to change the entry thing, as only "creatures" with Might and not "persons" with Might are excluded, while only "persons" and not "creatures" feel the tingle. Ugh!!!

I inserted "apparently" in the two spots since it doesn't change much of anything, but the logic is sound. "If any spell is cast... by any magus who was not involved..." There is never any exception listed to this. Invitations and tokens deal with entry and casting totals.


Just for the record, for those interested:

At phoenix, we've got magi 5 years out of gauntlet. One of them (Ok, she's a mercurian, that helps a little) knows Aegis at lvl 30, and, with aura, die, AL... can cast it with about penetration 10.
We've calculated that, after only 2-3 seasons, we'll be able to cast it with 30+ penetration by using Wizard's Communion (Sun Duration to boot, as per the errata).
Aside from the mercurian, none of the character was designed with any of this in mind.

Hmmm... Upon another reread it looks like I will have to upgrade the penetration thing back to where it was. The penetration penalty is the same as the casting total penalty. So if the casting total penalty is none, then so is the penetration penalty. What we have here is Y=X followed by a statement that if T, then X=0. That necessarily implies that if T, then Y=0, too.

I'll also have to adjust for "magical" being used. I forgot to do that before on the penetration penalty.

Okay, I'm going to turn this on it's head a bit

Can someone prove to me RAW that the Aegis doesn't need to penetrate as any other spell would. This would include the effect upon casting magic in foreign auras. Although I could see the aegis acting as a ward vs external magic.

The reason I argue these two is simple.
1 - Wards must penetrate (See Columbae in HoHS)
2 - Spells don't have magic resistance so can be bounced by a ward.
3 - If you say that you can strip the magic in an area to hinder a magic user without it needing to penetrate, how about stripping the air or the heat from an area. By extension, you could strip/supress these too without then needing to penetrate. Perdo(rego?)-Ignem sudenly becomes a deadly combination.

I think the need to penetrate with Aegis makes this a lot more interesting and Ceremonial casting bonuses and Wizards Communion a lot more useful.